Quadrature modulation without carrier
AssigneeUltrabit Communications LLC
InventorStephan V. Schell
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Abstract
Transmitters, receivers and associated methods are disclosed for providing phase and amplitude modulation in a carrier-less communication system (e.g., an ultra-wide band communication system). An approximate quadrature signal is provided by delaying the in-phase signal by an amount determined by various criteria, such as the bandwidths of the component signals, minimizing the mean square error between an approximate quadrature signal and the true quadrature signal, and minimizing the auto-correlation function of the in-phase signal.
Claims27
A method, comprising:
- obtaining an approximate quadrature signal by applying, by a transmitter, a delay to an in-phase signal;
- and
- summing, by the transmitter, the in-phase and the approximate quadrature signal;
- wherein the in-phase signal conforms to Rice's representation.
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A transmitter, comprising:
- a first signal path configured to generate an in-phase signal;
- a second signal path configured to apply a delay to the in-phase signal to generate an approximate quadrature signal;
- a summer configured to sum the in-phase signal and the approximate quadrature signal;
- and
- a transmitter unit configured to transmit the summed signal;
- wherein the in-phase signal conforms to Rice's representation, and wherein the bandwidths of the coefficients in the Rice's representation are substantially less than the center frequency in the Rice's representation.
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The transmitter of claim 10, wherein a value of the delay is approximately
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- f
- c
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- and wherein fc is a center frequency in the Rice's representation.
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A receiver, comprising:
- a first matched-filter matched to an in-phase signal;
- a second matched-filter matched to an approximate quadrature signal comprising the in-phase signal and a delay component;
- and
- a first analog-to-digital converters configured to receive a first output signals from the first matched-filter and to facilitate recovery of the in-phase signal from the first output signal;
- and
- a second analog-to-digital converter configured to receive a second output signal from the second matched-filter and to facilitate recovery of the approximate quadrature signal from the second output signal;
- wherein the in-phase signal conforms to Rice's representation.
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A receiver, comprising:
- a matched-filter configured to be matched to an in-phase signal;
- a first analog-to-digital converter configured to receive an output signal from the matched filter, wherein the analog-to-digital converter is further configured to facilitate recovery of the in-phase signal of the output signal;
- and
- a second analog-to-digital converter configured to receive the output signal from the matched filter, wherein the second analog-to-digital converter is further configured to facilitate recovery of an approximate quadrature signal of the output signal;
- wherein the first matched filter is configured to sample the output signal based at least on a first clock signal, wherein the second analog-to-digital converter is configured to sample the output signal based at least on a second clock signal comprising the first clock signal plus a delay component.
Dependencies are inferred from the claim text.